Inverse Rational
1. The problem is to find the inverse of the function $$f(x) = \frac{8x-4}{4+5x}$$.
2. Start by replacing $$f(x)$$ with $$y$$:
$$y = \frac{8x-4}{4+5x}$$
3. Swap the roles of $$x$$ and $$y$$ to find the inverse function:
$$x = \frac{8y-4}{4+5y}$$
4. Now, solve for $$y$$ in terms of $$x$$.
Multiply both sides by the denominator $$4+5y$$:
$$x(4+5y) = 8y - 4$$
5. Distribute $$x$$:
$$4x + 5xy = 8y - 4$$
6. Group terms involving $$y$$ on one side and constants on the other:
$$5xy - 8y = -4 - 4x$$
7. Factor $$y$$ on the left side:
$$y(5x - 8) = -4 - 4x$$
8. Divide both sides by $$5x - 8$$ to isolate $$y$$:
$$y = \frac{-4 - 4x}{5x - 8}$$
9. Simplify numerator:
$$y = \frac{-4(1 + x)}{5x - 8}$$
Thus, the inverse function is:
$$f^{-1}(x) = \frac{-4(1 + x)}{5x - 8}$$